Marihuana active compounds



Patented May 6, 1947 2,449,937 MARIHUANA ACTIVE COMPOUNDS Roger Adams, Urbana, Ill.

No Drawing. Application March 27, 1944, Serial No. 528,351

9 Claims.

My invention relates to organic chemical compounds for therapeutic uses and includes among its objects and uses the production of such com.. pounds having marihuana activity and greatly improved stability and uniformity in therapeutic strength as compared with crude marihuana from natural sources.

The red oil, sometimes also called crude cannabinol, derived from Cannabis satica, has been shown to contain a number of substances which are therapeutically inactive or toxic, as well as cannabidiol, cannabinol and hydrocannabinols of some sort, either originally present in cannabis or inadvertently generated in varying amounts by the treatment used to produce the red oil.

The complete formula for cannabidiol can be written thus:

H l H H OH H H C H 1(n) Cannabidjol I H C H H CH3 CH2 but it is customary to omit all the hydrogens directly bonded to the rings, and to indicate their presence by drawing the unconnected bonds at the position occupied by each carbon atom having two bonds extending outside the ring. Accordingly, the common structural formula for cannabidiol is as follows:

I OH

11:1(11) Cannabidiol OH; CH:

cannabinol is represented by the following formula:

6 l1(l1) cannabinol rived from cannabinol by adding four hydrogen atoms and thus eliminating two of the double bonds of the left ring. Thus the formula:

OH; CH;

Tetrahydrocaimabinol or homologue represents a tetrahydrocannabinol when R is normal amyl, or a homologue in case R is some other alkyl group,

The double bond in the left ring of cannabidiol and tetrahydrocannabinol has been shown only to make the diagram consistent as to valences. In the synthetic optically inactive tetrahydrocannabinol it occupies the position conjugated to the benzene ring, and it is believed probable that in the natural optically active form derived from cannabidiol it is in the position indicated at the left end of the ring though it may be in the next position upwards from that indicated.

The compounds of the present invention include hexahydrocannabinol and various homologues thereof, which may be represented by the following formula:

CH: CH;

Hexahydrocannabinol or homologue purpose by any suitable procedure, such, for instance, as that disclosed in my Patent No. 2,304,669, issued December 8, 1942.

EXAMPLE I A. Formation of tetrahydrocannabinols by isomerzzation of cannabidiol A solution of about 0.19 gram of p-toluenesulionic acid monohydrate and 3.14 grams of crystalline cannabidiol in 100 cc. of dry benzene was refluxed for one and one-half hours. At the end of that time the alkaline Beam test was negative. The benzenesolution was extracted'twice with about 5% aqueous sodium bicarbonate solution and twice with water. The benzene was then evaporated and the residue distilled under reduced pressure. Four fractions were collected, B. P. 169172 (0.03 mm.), having "essentially the same rotation [a]D 264 to 270.

Rotation-00694 grams made up to 5 cc. with 95% ethanol at 29 gave '(ZD-"3.70; 1, 1; [Mia -267.

B. Herahydrocannabinol by reduction-of 'tetmhydrocannabinol made =from natural cannabidz'ol fAfsolution of 3.14; g. of tetrah'ydrocannabinol HE -160, which had been distilled in 'high vacuoinan all-glassapparatus, in 50 cc. of glacial acetic acid was reduced with hydrogen at room temperature, using 0.1g. ct -platinum oxide as catalyst. Hydrogen corresponding to 0.96 mole per mole'zof tetrahydrocannabinol was absorbed in about four hours, after which hydrogenation continued toproc'eed but at a very much slower rate. After absorption of one mole equivalent of hydrogen, the solution -wasfiltered and atheiacetic acid r'emovedzin vacuo. The hexahy- '.drocann'abinol for-meda colorless, highly viscous resin, B. P. 153-155 (0.1 mm.) (bath temp. .180..185);'refractive index n 1. 53. 48.

iAnaZ.- Calc. for :Czrl-IazOz: C, 79.69; H, 1019.

It was found that .regardle'ss of {the initial ro- =tation of the optically active tetrahydriocanna- -binol-used, the hexahydro product always hadies- 'se'ntially the same specificirotati'on,=whenderived 'ther'sidue (l hydroxy 3 n -'amyl 9 methyl- 17,8,9,I0 tetrahydro 6 dibenzopyrone) after puri-' fication by recrystallization from ethyl acetate, is obtained as white needles with'amelting point of mm-181 C. If "desired; thebilide i'sidueaiftr crystallization from methanol may be converted to: the pyran as described-below.

A' suspension of about 9 grams of l-hydroxy- 3-n-amyl 9-methyl-7,8;9,-10-tetrahydro 6diben zopyrone in 140 cc. of solventmade upofiabout '3 parts .ofdry benzene and 1 part of"dry"di'-nbutyl ether is next'n'iixed Witli'a'solutionof Grighard reagent made up from about 9 grams of magnesium and 22.5 cc. of methyl iodide in '75 cc. of dry ether and the total mixture then refluxed for about eight hours. After refluxing, the reaction mixture is poured onto iced ammonium chloride solution, the organic layer separated, the

aqueous layer extracted once with benzene and the combined benzene solutions washed successively with water, dilute aqueous sodium bicarbonate and water. The organic solvent (benzene, etc.) is then evaporated and the residue dissolved or taken up in about cc. of petroleum ether (B. 1P.-60- 100 C.). About -10drops of 48 'per'cent aqueous hydrobro-mic acidis next added to the petroleum ether solution which is then boiled on a hot plate for about thirty mi utes while maintaining the volume substantially constant byaddition of more solvent as necessary. .Aiter separation of the reaction solution, e. g., by dec'antation, from a small amount of insoluble material, the solvent is evaporated in the usual manner and the residue, 1-hydroxy-3-namyl-6,6,9-trimethyl-7,8,9,lo-tetrahydro 6 di benzopyran distilled. This product is obtained as a .viscous oil, B. P. -180 C. (0.02 mm.), (bath temperature -200 C.); refractiveindex n5 1.5567. 'On standing it'solidifies and may be purified by recrystallization from glacial "acetic acid forming white crystals with a melting' point of about-72-'7-3' C. B. Hexahydrocannabinol by reduction of l-hydrozcy-3-n-amyl 6,9 trimethyZ-7;8,9,10-tetrahydro-6 -dz'ben-zopymn A solution of about 3 grams ofthe tetrahydro derivative prepared as described above, in 50cc.

of glacial --ace tic acid is reduced in the usual -manner--at room temperature in the Presence of anc e' with the procedure set forth above in E1:- -ample-lI. This procedure calls for (a) condensing =an a1kyl cyclohexanone-2 carboxylate with a 1,3-dihydroXy B-aIkyLbenZene to form the i corresponding dibenzopyrone product, (0) treating the -pyrone product-"of stepa) with .a lower alkyl Grignard reagent to form the corresponding tetrahydrodibenzopyran product and (c) reducing the pyran product of step (b) to form the corresponding hexahydrodibenzopyran.

ExampleIII A. PuZegone-orcinol condensation product About 3.1 grams of pulegone ([u] +24.3),

2.5 grams of 1.3 dihydroxy-5-methyl benzene (orcinol), 0.98 gram of phosphorous oxychloride (0.33 mole proportion) and-20 cc. of dry benzene are first mixed together and then refluxed for about four hours. The reaction mixture is then poured into an excess of aqueous sodium "bicarbonate and warmed on a steam bath until the phosphorus derivatives are decomposed. After cooling, the benzene layer is separated and the aqueous layer "extracted with a mixture of benzene and ether. The organic solvent solutions containing the desired product are then combined, extracted with 2 per cent aqueous sodium hydroxide and the solvent removed in the usual manner. The residue is then vacuum distilled at about 5 mm. (bath 202-215 C.) at about 170-180 C. The final product obtained is optically active, the specific rotations in ethanol varying from about [a] |33.5 to +90.4 depending on the boiling point of the specific fraction tested.

(a) Similar to the above preparation except for the use of an 0.47 mole proportion of P0013, fractions were obtained having rotations in ethanol or about [a] +66.0 to +76.9.

B. PuZegone-olioetol condensation product About 5 grams of pulegone, 6 grams Of 1.3-dihydroxy-5-n-amylbenzene (olivetol), and 1.5 grams of phosphorus oxychloride (0.3 mole proportion) are refluxed in benzene solution for about four hours. The reaction product, is then worked up, i. e., treated with sodium bicarbonate solution, etc, as set forth in Example I and vacuum distilled at about 2 mm. (bath 225- 233 C.) at 190-200 C. The final product obtained is an optically active tetrahydrocannabi- 1101 The specific rotations and indices of refraction of the product obtained using the 0.3 mole proportion of POClz set forth above vary as follows: fraction (1) boiling point 190-195 C., specific rotation in ethanol [a] |'72.O, refractive index n 1.5509; fraction (2) boiling point 19519'7 C., specific rotation in ethanol [cl 4-770, refractive index n 1.5519; fraction (.3) boiling point 197-200 C., specific rotation in ethanol [a] +73.0 refractive index n 1.5529.

Similar to the above preparation except for the use of an 0.53 mole proportion of POCls, fractions were obtained having specific rotations in ethanol of about [a] +70.0 to +70.4.

Similar to the above preparation except for the use of an 0.76 mole proportion of POCls and with six hours of refluxing, fractions were obtained having rotations of about [u] +43.1 to +53.1.

C. Hemahydrocanna binols by reduction of pulegone condensation products The same procedure outline in Example 1113 may be employed to produce the hexahydro derivative of either the pulegone-orcinol condensation product of Example IIIA, or the pulegoneolivetol condensation product of Example 11113.

Other derivatives may be prepared in accordance with the procedure set forth above in Example III. This procedure calls for (a) condensing optically active pulegone with a 1,3-dihydroxy-5-alkyl benzene to form the corresponding dibenzopyran product and (b) reducing the pyran product of step (a) to form the corresponding hexahydrodibenzopyran. The 3-hexyl derivative may be prepared in accordance with Example III by (a) condensing optically active pulegone with a 1,3-dihydroxy-5-hexyl benzene to form the corresponding dibenzopyran product and (b) reducing the pyran product of step (a) to form the corresponding hexahydrodibenzopyran.

EXAMPLE IV Tetrahydrocannabinol monoacetate A. A mixture of tetrahydrocannabinol [ch -164 was heated with acetic anhydride and a little fused anhydrous sodium acetate for two hours and worked up in the usual manner. The desired acetate product is a colorless, viscous oil, B. P. 156-158 (0.07 mm) (bath temperature 175); refractive index n 1.5232.

Rotation.0.0281 made up to 5 cc. with ethanol at 34 gave an 1.88; 1, 2; [ch --167. B. Tetrahydrocannabinol [a]D 240 was acetylated as described in A above. This product obtained from the higher rotating isomer is a colorless, viscous oil, B. P. 172-174 (0.08 mm.) (bath temp. 195); refractive index n 1.5242. Rotation.0.0373 g. made up to 5 cc. with 95% ethanol at 34 gave cm 1.72; 1, 2; [0:11: 229.

The same procedure outlined above may be employed in producing esters from tetrahydrocannabinol derived from any source or from the hexahydro compound disclosed herein.

EXAMPLE V Tetrahydrocannabinol monome'thyl ether A. Tetrahydrocannabinol [ch -164 was refiuxed for 15 hours with anhydrous potassium carbonate and methyl iodide in acetone solution. The ether product was purified from unchanged tetrahydrocannabinol by means of Claisens potash and yields a colorless, viscous oil, B. P. 168- (0.08 mm.) (bath temperature -195") refractive index 11 1.5323.

Rotdtion.0.0395 g. made up to 5 cc. with 95% ethanol at 32 gave an 1.31; 1, 1; [ch 166".

The same procedure outlined above may be employed in producing ethers from tetrahydrocannabinol derived from any source, and any of these ethers may be reduced to the corresponding hexahydro compound by the procedure of Example 113 hereinabove.

, This application is a continuation in part of my copending applications: Serial No. 358,306, filed September 25, 1940; Serial No. 401,655, filed July 9, 1941; Serial No. 401,656, filed July 9, 1941; Serial No. 440,971, filed April 29, 1942.

Without further elaboration, the foregoing will so fully explain the invention that others may readily adapt the same for use under various conditions of service.

I claim:

1. Hexahydro dibenzopyrans having the formula:

t on

in which R is an alkyl group having from one to eleven carbon atoms, and R1, R2 and R3 are lower alkyl groups.

2. A pyran compound represented by the following formula:

I OY

where R represents a lower alkyl group, R1 is selected from the group consisting of hydrogen and lower alkyl groups, R2 is selected from the group consisting of hydrogen and alkyl groups containing one to ten carbon atoms and Y is selected from the group consisting of hydrogen and lower alkyl and acyl groups.

3. A pyran compound represented by the formula of claim 2 in which R2 is an alkyl group containing four carbon atoms.

4. An optically inactive pyran compound represented by the formula of claim 2 in which R2 is an alkyl group containing five carbon atoms.

5. A pyran compound represented by the following formula:

CHa C where R represents a lower alkyl group, R1 is selected from the group consisting of hydrogen and lower alkyl groups, R2 is selected from the group consisting of hydrogen and alkyl groups containing one to ten carbon atoms and Y is a lower alkyl group.

9. A pyran compound represented by the formula in claim 8, where R represents a lower alkyl group, R1 is selected from the group consisting of hydrogen and lower alkyl groups, R2 is selected from the group consisting of hydrogen and alkyl groups containing one to ten carbon atoms and Y is a lower acyl group.

ROGER ADAMS.

REFERENCES CITED The following references are of record in the file of this patent:

FOREIGN PATENTS Country Date British Sept. 7, 1942 OTHER REFERENCES Number 

